Distance Measurements on Orthogonally Spin-Labeled Membrane Spanning WALP23 Polypeptides

P. Lueders, H. Jäger, M.A. Hemminga, G. Jeschke, M. Yulikov

Research output: Contribution to journalArticleAcademicpeer-review

47 Citations (Scopus)

Abstract

EPR-based Gd(III)-nitroxide distance measurements were performed on a series of membrane-incorporated orthogonally labeled WALP23 polypeptides. The obtained distance distributions were stable upon the change of detection frequency from 10 GHz (X-band) to 35 GHz (Q-band). The alpha-helical pitch of WALP23 polypeptide could be experimentally observed, despite the flexibility of the two spin labels. The spectroscopic properties of Gd(III) ions and nitroxide radicals allow detecting both types of paramagnetic species selectively in different EPR experiments. In particular, this spectroscopic selectivity allows for supplementing Gd(III)-nitroxide distance measurements with independent checks of polypeptide aggregation and with measurements of the local environment of the nitroxide spin labels. All mentioned additional checks do not require preparation of further samples, as it is the case in the experiments with pairs of identical nitroxide spin labels.
Original languageEnglish
Pages (from-to)2061-2068
JournalThe Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
Volume117
Issue number7
DOIs
Publication statusPublished - 2013

Keywords

  • electron double-resonance
  • trichogin ga-iv
  • alpha-helical peptides
  • dipole-dipole interactions
  • islet amyloid polypeptide
  • field pulsed epr
  • hydrophobic mismatch
  • phospholipid membrane
  • gd3+ complexes
  • spectroscopy

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